US STOCKS-Wall St slips on worries over tax plan's progress

Nov 17 (Reuters) - Wall Street indexes were under pressure on Friday as investors were skeptical about the Republicans' efforts to pass the tax bill.

The House of Representatives took important steps on Thursday toward the biggest U.S. tax-code overhaul since the 1980s, approving a broad package of cuts, while a Senate panel advanced its own version of the legislation.

Tax debate shifts to the Senate, where the plan has already faced resistance and the Republican majority is much slimmer.

"The market is still kind of nervous with respect to the tax bill moving to the next stage," said Massud Ghaussy, director at Nasdaq Advisory Services.

"The GOP can afford only two defections and they are not expecting any Democrats to vote for it."

A Reuters poll showed that nearly two-thirds of the more than 60 economists interviewed did not see the Republicans pushing major tax cuts through Congress this year.

At 12:30 p.m. ET (1630 GMT), the Dow Jones Industrial Average was down 81.71 points, or 0.35 percent, at 23,376.65, the S&amp;P 500 was down 2.57 points, or 0.10 percent, at 2,583.07 and the Nasdaq Composite was up 3.08 points, or 0.05 percent, at 6,796.37.

Strong earnings and good economic data have underpinned much of the rally this year. The S&amp;P 500 has risen about 15 percent this year, its biggest gain in four years.

"We've been seeing a decent run-up in stocks recently, and it's just wobbly couple of days," Ghaussy said.

The technology index weighed the most on the S&amp;P 500, falling 0.46 percent.

Shares of Twenty-First Century Fox rose 3.82 percent after sources said Comcast and Verizon had expressed interest in acquiring a significant part of the company's assets.